Electrical connecting device



June 30, 1931. D. w. JOHNSON ET AL 7 1,812,343

ELECTRICAL CONNECTING DEVICE Filed May 11, 1929 INVENTORS ARVID H.NERODAVID W.JOHNSON Patented June 30, 1931 UNITED STATES PATENT OFFICE DAVIDW. JOHNSON, OF NEWINGTON, AND ARVID H. NERO, OF WEST HARTFORD, CON-NECTICUT, ASSIGNORS TO THE ARROW-HART & HEGEMAN ELECTRIC COMPANY,

OF HARTFORD, CONNECTICUT, A CORPORATION OF CONNECTICUT ELECTRICALCONNECTING DEVICE Application filed May 11, 1929. Serial No. 362,402.

This invention relates to electric connecting devices and moreparticularly to means for facilitating the insertion of the blades of anattachment plug cap into the contact aper tures of electric connectingdevices, such as attachment plug bodies, flush receptacles, outlets,cord connectors and the like. In brief, by providing the face of anattachment plug body, flush receptacle, cord connector, outlet or likedevice with grooves leading to the contact apertures, according to ourinvention, we provide an effective and certain means whereby theinsertion of the attachment plug cap contact blades into an attachmentplug body or like device is facilitated. The invention finds particularuse when the attachment plug body, flush receptacle, cord connector orlike device is inconveniently located, for example, behind furniture oroverhead. Devices of this type inthe prior art have been subject to manydisadvantages and it is an object of our invention to provide a grooveto guide the attachment plug cap contact blades into contact aperturesof an attachment plug body or like device in a more direct and certainmanner than heretofore.

Other objects will become apparent as the invention is described inconnection with the 5 accompanying drawings in which Fig. 1 is a topplan View of an attachment plug body provided with a spiralgrooveaccordingto our invention.

Fig. 2 is a broken elevation section view of the plug shown in Fig. 1with the section taken on line 22 of Fig.1. The attachment plug cap andthe bottom of theplug body are .shown in dotted lines.

Fig.3 is a broken elevation section view of the head of the attachmentplug body shown in Fig. 1, with the section taken on line 3-3 of Fig.1.

Fig. 4 isan elevation section view of the head of'the attachment plugbody shown in Fig. 1 with the'section taken on line 4-4 of Fig. 1. v

Referring now to the drawings it will be apparent that our invention maybe applied to an attachment plug body of the customary structuralfeatures, that is. with the body portion 10 cylindrical and flaring outto an enlarged head portion 11 which is also cylinblades 14, 15 on aconventional attachment plug cap 16.

The flat top face of the attachment plug body is hollowed out around thecontact apertures 12 and 13 to form inclined grooves 17 18, 19 and 20,the sides of which grooves slope downwardly from the periphery of theplug and on one side, on the other side, downwardly from crooked orstemmed diamondshaped barrier 21 skewed to the apertures and separatingthe grooves and apertures. The stems 22, 23 of the barrier compriseextensions of those parallel sides of the diamond portion which areoblique to the contact apertures. These stems extend to the periphery ofthe plug. By making the barrier skewed, as described, the chance ofplacing both the contact prongs upon it is minimized. It will be notedthat we make the inclined grooves 19, 20 with long gently sloping pathswhich extend from the points of intersection of the stems 22, 23 withthe periphery of the plug, downwardly to the contact apertures. We makethe grooves 17 18 with steep short paths which extend in the directionopposite to the paths 19, 20, upwardly from the contact apertures tothose points of the diamond barrier from which the stems 22, 23 extend.When the blades of an attachment plug cap are pressed against the faceof the attachment plug body in attempting to insert the blades in theapertures 12, 13, the blades will normally rest upon some portion of thegrooved surfaces and the person who is holdmg the plug cap, in rotatingthe cap as is usual in attempting to insert the blades, 14, 15 into thecontact apertures 12 and 13, will naturally allow the blades to beguided by the grooves into the apertures 12, 1

Itshould be noted in the construction just described there is a minimumamount of flat surface for the contact fingers to rest upon and hencethe contact prongs or blades will practically always fall upon a portionof the grooves 17, 18, 19 and 20, and be guided thereby into theapertures 12, 13 as described. It

should also be noted that the short grooves are approximately inalignment with the contact apertures but the long grooves are ob liqueto theapertures and extend from them to the periphery of the plug at apoint across and beyond the median line between the contact apertures.By the different angular approach of the long and short grooves to thecontact apertures, we make use of the natural tendency of personsattempting to connect the plug and cap, to rotate or twist the cap untilthe blades find the apertures. It

should therefore be noted that in case the prongs of an attachment plugcap are placed on the face of our plug so as to fall on the me-- dianline between the contact apertures, the prongs even then will fall onsurfaces which decline into the contact apertures. Thus, the prongs willbe speedily guided thereinto.

While we have shown our invention as applied to an attachment plug body,it will be apparent that our invention may as well be applied to cordconnectors, outlets, flush receptacles, and the like, whether round inshape or otherwise, and in practicing our invention we apply it toarticles of those types, as well as to attachment plugs.

If preferred, contact apertures of the double T, L, or circular typesmay be used in:- stead of the rectangular apertures which we have shownby way of"illustration and not with intent to limit our invention torectangular slots.

Therefore we do not limitour invention to the specific embodiment.shown, but we claim 1. An electric connecting device having contactapertures in its face adapted to receive contact blades, a long and ashort groove leading to each aperture.

2. An electric connecting device "having contact apertures in its faceadapted to receive contact blades, a long and a; short groove leading toeach aperture, said long grooves being oblique to the contact aperturesand said short grooves being in approximate alignment with saidapertures.

3. An electric connecting device having contact apertures in its faceadapted to receive contact blades, a long and a short groove leading toeach aperture, and a barrier separating said grooves and apertures.

1 4. 11 electric connecting device having contact apertures in its faceadapted to 'receive contact blades, a long and a short groove leading toeach aperture, said long grooves being oblique to the contact aperturesand a barrier separating said grooves and apertures.

5. An electric connecting device having contact apertures in its faceadapted to receivecontact blades, a long and a short groove leading toeach aperture, and a. crooked bar-

